Enhanced climate seat with asymmetric thermal management system and method

ABSTRACT

A thermally conditioned seat includes a seat portion constructed from a first material which includes a seat support structure that has a central support region and adjacent side bolsters laterally spaced apart from one another a width. A recess is provided in the central support region and includes an aperture. A porous material is arranged in the recess against the first material. A second material is arranged against the first material and the porous material. A cover includes an air permeable layer and an aesthetic layer that provides an exterior seating surface. The air permeable layer is arranged against the second material and the aesthetic layer has perforations. A blower is associated with the seat portion and is in fluid communication with the aperture. The blower is configured to supply a fluid through the aperture to the porous material through the recess. The fluid is configured to pass from the porous material to the air permeable layer and out the perforations.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application from U.S. application Ser.No. 15/150,543 filed on May 10, 2016, which claims priority to U.S.Provisional Application No. 62/160,327, filed on May 12, 2015 and areincorporated herein by reference.

BACKGROUND

This disclosure relates to an enhanced thermally conditioned climateseat and a method for operating the same.

Thermally conditioned seats are increasingly used in vehicles to providea more comfortable microclimate for vehicle occupants. In such seats itis common to heat or cool both the seat bottom and seat backsimultaneously and uniformly in response to a user input via a switch.In one type of thermally conditioned seat, the heater in the seat backmay be separately energized with the heater in the seat bottom off.

A variety of approaches have been used to cool a seat. In one example,generally, cooled air flows through passages in the seat to providecooled fluid through perforations in the exterior of the seat's cover.The cooled fluid may be provided from the vehicle heating, ventilationand cooling (HVAC) system or by using a thermoelectric device, such as aPeltier device.

In one type of cooling arrangement, a bag is supported on a polyurethanefoam seat portion. Side bolsters are provided on either side of the seatportion. Typically, the bag extends the entire width of the seat portionto the bolsters. The bag includes a plastic exterior providing a cavitywithin which a breathable spacer material, such as a woven textile, isarranged to keep the cavity opened so that air may pass through thecavity. Holes are provided in the bag's plastic exterior. A cover isarranged over the bag and seat portion. The cover includes an airpermeable layer adjacent to the bag and an aesthetic layer that includesperforations. A blower supplies cooled fluid to the bag and flowsthrough the breathable spacer material and out holes in the plasticexterior. The cooled fluid is then distributed by the air permeablelayer and out the perforations in the aesthetic layer.

In another type of cooling arrangement, channels are provided in thefoam seat portion. The cover is arranged on the seat portion over thechannels, and the blower provides cooled fluid to the channels. Thecooled fluid flows from the channels into the air permeable layer andout the perforations in the aesthetic layer.

SUMMARY

In one exemplary embodiment, a thermally conditioned seat includes aseat portion constructed from a first material which includes a seatsupport structure that has a central support region and adjacent sidebolsters laterally spaced apart from one another a width. A recess isprovided in the central support region and includes an aperture. Aporous material is arranged in the recess against the first material. Asecond material is arranged against the first material and the porousmaterial. A cover includes an air permeable layer and an aesthetic layerthat provides an exterior seating surface. The air permeable layer isarranged against the second material and the aesthetic layer hasperforations. A blower is associated with the seat portion and is influid communication with the aperture. The blower is configured tosupply a fluid through the aperture to the porous material through therecess. The fluid is configured to pass from the porous material to theair permeable layer and out the perforations.

In a further embodiment of any of the above, the first material ispolyurethane foam.

In a further embodiment of any of the above, the seat portion is one ofa seat bottom or a seat back.

In a further embodiment of any of the above, the width is a firstlateral width. The porous material has a second lateral width that isless than 75% of the first lateral width.

In a further embodiment of any of the above, the second lateral width is35-65% of the first lateral width.

In a further embodiment of any of the above, the porous material is abreathable spacer material.

In a further embodiment of any of the above, the second material isfleece.

In a further embodiment of any of the above, heating elements aresupported on the fleece on a side opposite the porous material.

In a further embodiment of any of the above, the air permeable layer andthe aesthetic layer are joined to one another at stitched seams.

In a further embodiment of any of the above, a thermoelectric device isarranged between the blower and the recess. The thermoelectric device isconfigured to cool the fluid.

In a further embodiment of any of the above, the second material isimpermeable and has an opening. The fluid is configured to pass from theporous material through the opening to the air permeable layer and outthe perforations.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure can be further understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is a perspective view of a seat embodiment illustrating first andsecond thermal conditioning modules.

FIG. 2 is a perspective view of a porous material.

FIG. 3 is an elevational view of a second material with heating elementsomitted for clarity.

FIG. 3A is a graph depicting a typical perceived comfort of an occupant,which illustrates the occupant back and lower region comfort in responseto a symmetric thermal management approach.

FIG. 3B is a graph depicting a typical perceived comfort of an occupant,which illustrates the occupant back and lower region comfort in responseto an asymmetric thermal management approach.

FIG. 4 is a schematic illustration of a focused conditioning zonerelative to a seat support surface.

FIG. 4A is cross-sectional view through a seat portion and the firstthermal conditioning module illustrating an initial distributionprovided on an “A”-surface of a seat cushion.

FIG. 4B is cross-sectional view through a seat portion and the firstthermal conditioning module illustrating an initial distributionprovided on a “B”-surface of the seat cushion.

FIG. 5 is a schematic view of an example thermal conditioning system.

The embodiments, examples and alternatives of the preceding paragraphs,the claims, or the following description and drawings, including any oftheir various aspects or respective individual features, may be takenindependently or in any combination. Features described in connectionwith one embodiment are applicable to all embodiments, unless suchfeatures are incompatible.

DETAILED DESCRIPTION

One example vehicle seat 10 is schematically illustrated in FIG. 1. Theseat 10 includes a seat bottom or cushion 12 and a seat back 14. Theseat back 14 includes a seat portion having a central support region 16with bolsters 18 laterally spaced apart from one another a first lateralwidth 26. A headrest 20 is provided on the central support region 16.The bottom 12 includes a seat portion having a central support region 21provided with laterally spaced apart bolsters 24 spaced apart a widthand a thigh bolster 22, which may be adjustable with respect to thecentral support region 21. The seat portions are constructed from afirst material, such as polyurethane foam.

A first thermal conditioning assembly 28 is provided in the seat back14, and a second thermal conditioning assembly 30 is provided in theseat bottom 12. The thermal conditioning assemblies are shown in phantombeneath the seats exterior surface in FIG. 1. In the example, each ofthe first and second thermal conditioning assemblies 28 a, 28 b includeboth first and second heating and cooling devices 28 a, 28 b and 30 a,30 b, respectively. In the case of the example seat back 14, the coolingmay be provided by a thermal cooling module that has an active coolingelement, for example, a Peltier device, and a blower. In the case of theexample seat bottom, the cooling may be provided by convection coolingusing a blower with ventilation only. It should be understood, however,that different and/or additional heating and/or cooling components maybe used than shown. For example, the seat bottom 12 and/or seat back 14may not include a heating device.

The seat back is referenced in the following illustrated example,although the disclosed embodiment may also be used in the seat bottom. Aporous material 34 is provided in a recess 32 of the polyurethane foamseat portion. The porous material 34 extends a second lateral width 35that is substantially less than the first lateral width 26, for example,less than 75%. In another example, the second lateral width 35 is35%-65% of the first lateral width 26. As a result, the porous material34, which distributes conditioned fluid to the occupant through the seatsupport surface, provides much more focused cooling of key thermallyresponsive areas of the occupant's body, providing a quicker thermalresponse in areas most needed to achieve comfort.

The porous material 34 is a breathable spacer material, for example,constructed from woven textiles. The breathable spacer material includeswoven layers spaced apart from one another, as best shown in FIG. 2.Pile yarns interconnect the woven layers. The number, size, orientationand material characteristics of the pile yarn determine the cushioningcharacteristics provided by the porous material. Voids are providedbetween the pile yarns to permit fluid flow. Example breathable spacermaterials are a reticulated foam, or 3-D MESH® available from MuellerTextiles.

Referring to FIG. 3, a second material 36, such as a fleece or felt,supports heating elements 42, which provide the heating devices 28 b, 30b, as shown in FIG. 1. It should be understood that other materials maybe used for the second material 36, such as a scrim or heater elementcarrier material. The second material 36 includes a central portion 38secured to the central support region 16 over the porous material 34,shown in phantom in FIG. 3. Wings 40 extend from the central portion 38and are supported on the bolsters 18. The heating elements 42 areomitted from FIG. 3 for clarity, but are shown in FIG. 1.

The second material 36 acts as a barrier layer and includes openings 44a-44 e, collectively referred to as “openings 44,” that permit fluid topass from the recess 32 through the porous material through the secondmaterial 36. The second material 36 is otherwise substantiallyimpermeable, in one example embodiment, which enables more focusedcooling initially than that provided by the areal dimensions of theporous material 34 (e.g., FIG. 3 or 4B). In another example embodiment,the second material 36 may be substantially permeable, which providesinitial cooling that corresponds to the areal dimensions of the porousmaterial 34 (e.g., FIG. 4A).

It is difficult to objectively quantify a person's thermal state, e.g.,sensations and comfort, (collectively referred to as “occupant thermalcondition”) such that a thermal conditioning system can be automaticallycontrolled to achieve a desired thermal sensation and comfort for thatperson. As one example, an occupant thermal condition or state can be acondition of sensing a hot or cold temperature, or changes intemperature. As another example, an occupant thermal condition or statecan be a condition of feeling comfortable or uncomfortable, a level ofcomfort, or a change in a level of comfort. One widely recognizedapproach that attempts to objectively quantify a person's thermalcondition is referred to as the Berkeley Sensation and Comfort Scale(“Berkeley scale”), described in, for example, Arens E. A., Zhang H. &Huizenga C. (2006) Partial- and whole-body thermal sensation andcomfort, Part I: Uniform environmental conditions. Journal of ThermalBiology, 31, 53-59. It should be understood that other approaches can beused to quantify an occupant's thermal condition.

Using the Berkeley scale, thermal sensation is quantified from +4 to −4by a person. A more positive number corresponds to an increasing degreeof perceived heat, and a more negative number corresponds to anincreasing degree of perceived cold. High positive or negative numbersare indicative of painfully hot or painfully cold conditionsrespectively. A zero indicates the person is neutral as to any thermalsensation. Thermal comfort on the Berkeley scale is quantified from +4to −4 by a person, where a +4 indicates a person is “very comfortable,”and a −4 indicates a person is “very uncomfortable.”

FIG. 3A graphically depicts a typical perceived comfort of an occupantand illustrates the difference between occupant back and lower regioncomfort in response to a typical symmetrical thermal managementapproach. More cooling power is needed to overcome the back metabolicheat rate, since the skin temperature of the back tracks more closely tothe core body temperature.

Different areas of the body, for example, the back may perceive comfortdifferently or respond at a different rate to a thermal input. So, forexample, rather than indiscriminately cooling the whole back, theopenings (whether provided via the “A”-surface or “B”-surface) are sizedand placed strategically at locations that correspond to thermallyreceptive areas of an occupant's back that will be more responsive tocooling and induce a quicker overall feeling of thermal comfort. Forexample, the openings 44 a are positioned to align with the shoulderblades, the openings 44 b align with the spine, the openings 44 c, 44 eare spaced along the sides of the back, and the openings 44 d align withthe small of the back.

Referring to FIG. 4, a cover 48 includes an air permeable layer 52 andan aesthetic layer 50, which are typically secured to one another at asewn seam. Perforations 54 are provided in the aesthetic layer 50,typically perforate leather, to permit cooled fluid to pass from the airpermeable layer 52 through the perforations 54 to an exterior seatingsurface 51 to cool the seated occupant. In one example, the airpermeable layer 52 is provided under the perforations 54 on the centralsupport region 16 of the seat, but not on the bolsters.

Referring to FIG. 4A, a perimeter 49 of a cover 48 of the seat bottom 12is schematically illustrated. The cover 48 includes perforations 54(only some shown for clarity) across an area A1, which covers thecentral support region 21. The porous material 34 has a perimeter 33about an area A2 to provide focused thermal conditioning with respect tooccupant. The area A2 is less than 50% of the area A1, for example, andin one embodiment, the area A2 is 20%-50% of the area A1. The aboverelationship between first and second areas A1, A2 may also be used forthe seat back 14.

In the example, the porous material 34 is arranged against or inengagement with the seat portion and the second material 36. The airpermeable layer 52 is arranged against the second material 36 and theaesthetic layer 50. The porous material 34 acts as a plenum, and thesecond material 36 blocks the flow of fluid to all but the morethermally receptive parts of the occupant's body through the openings44, as illustrated by large arrows F1. Then, over time, the coolingfluid is distributed through the air permeable layer 52 outward to theentire first lateral width 26, providing sustained cooling of theoccupant's body, as illustrated by small arrows F2.

One or more apertures 56 are provided in the seat portion. A blower 58includes an outlet 62 that is received in the aperture 56. “Blower” and“fan” are used interchangeably in this disclosure. A foam gasket 64 maybe provided between the outlet 62 and the seat portion for bettersealing. The blower 58 receives fluid from an inlet 66, which may bepositioned beneath the seat 10, and supplies the inlet air through athermoelectric device (TED) 60, such as a Peltier device, to cool thefluid.

The above described embodiment achieves focused delivery of conditionedair to the occupant along the “A”-surface of the seat foam. Alternateembodiments for asymmetric conditioning could utilize “B”-surfacedistribution where channels 67 or pocket of distribution occurs alongthe bottom side of the foam and is distributed to the “A”-surface via anarray of through holes 69, as shown in FIG. 4B. Elements in FIG. 4B thatare common to FIG. 4A use the same numerals. The second material 136 ispermeable in the embodiment shown in FIG. 4B. The through holes 69 canbe located to allow conditioning to the key sensory mechanisms of thebody (i.e. along the spine or other areas of high thermal receptorconcentration) and a fast response based targeting the human thermalphysiology.

A “push” system for the cushion is described in the above embodiments.It should be understood that other embodiments may also be used, such asa “pull” system in the cushion to pull cabin air past the occupant intoand out of the seat. A pull or push passive ventilation system in theseat bottom can be used in combination with an active cooling system inthe seat back to provide asymmetric thermal conditioning. A push systemmay be used in the seat bottom in embodiments where active cooling isadded.

A high performance embodiment may comprise asymmetric coolingcomplimented with a pull ventilation strategy. In this case, multipleTEDs are used to push active conditioning in the back along with anadditional blower (or set of axial fans) to pull air flow from the cabinacross the occupant into the seat. In the seat bottom, a single TED (orfewer TEDs than in the seat back) are used to push active conditioningin the seat bottom along with an additional blower (or set of axialfans) to pull air flow from the cabin across the occupant into the seat.

An example thermal conditioning system 68 is illustrated in FIG. 5. Theheating elements 42, blowers 58 and TEDs 60 are in communication with acontroller 70, which receives the command signals from an input 72. Inone example, the seat back 14 may have a pair of TEDs 60 and the seatbottom 12 may have none. In another example, the seat back 14 may have apair of TEDs 60 and the seat bottom may have one TED. In a lower costembodiment, the seat back 14 is conditioned with one TED, and the seatbottom is conditioned passively with a blower only. Thus, it should beunderstood that various combinations of TEDs, blowers and heatingelements may be used to achieve the desired level of heating/cooling.Generally speaking, however, the seat back 14 will have more heattransfer capability than the seat bottom 12.

A neck conditioning device may be incorporated into the headrest andcontrolled by the same controller 70, as disclosed in, for example, U.S.application Ser. No. 14/824,154, entitled, “VEHICLE HEADREST THERMALCONDITIONER,” filed Aug. 12, 2015 and assigned to the present applicant,which is incorporated herein by reference in its entirety. The neckconditioner can be used in combination with a climate seat havingasymmetric thermal management to further maximize occupant comfort andinitial sensation.

The input 72 may be a 3-position switch for the level of heating/coolingand a 2-position switch for selecting between heating or cooling modes.The blower 58 may be controlled independently, if desired. Differentand/or additional inputs may be used, including sensors. One exampleinput is provided by a passive infrared (PIR) sensor to obtain aninfrared (IR) image of a face of the occupant, as disclosed in U.S.Provisional Application Ser. No. 62/316,938, entitled “OCCUPANT THERMALSTATE DETECTION AND COMFORT ADJUSTMENT SYSTEM AND METHOD,” filed on Apr.1, 2016, which is incorporated herein by reference in its entirety.Accordingly to that disclosure, the controller 70 can be used todetermine segments of the thermal image corresponding to the nose of theoccupant and surrounding cheeks and forehead, for example. The systemdetermines a difference in the nose temperatures and the surroundingcheeks and/or forehead, and determines the thermal state of the occupantbased on the difference. The system monitors a trend in the thermalstate, and adjusts a rate of heating or cooling of the occupant usingthe disclosed asymmetrical thermal system based on the occupant'sthermal state and trend in the state. Other detection systems may beused to provide autonomous control of the disclosed asymmetrical thermalsystem, if desired.

An example method of conditioning the seat 10 using the thermalconditioning system 68 includes operating the first cooling device 28 ain the seat back 14 to provide a first heat transfer rate 76 (q₁). Theseat back needs more cooling than the seat bottom to reach localizedoccupant comfort, thus providing thermal conditioning in a substantiallyproportional manner to the occupant. Overcooling occurs faster in theseat bottom than the seat back at equivalent cooling power. Thus, thecooling of the seat back is prioritized over cooling of the seat bottomto reach occupant thermal equilibrium. To this end, the second coolingdevice 30 a in the seat cushion 12 is operated to provide a second heattransfer rate 78 (q₂) simultaneously with and different than the firstheat transfer rate 76. In the example, the first heat transfer rate 76is greater than the second heat transfer rate 78 to provide more coolingto the occupant's back compared to their lower region, including thebuttocks and the legs to compensate for the body's natural thermalphysiological response, as depicted in FIG. 3B.

During periods of rest, for example prolonged vehicle driving, heatproduced by core organs can be orders of magnitude greater than heatproduced by peripheral tissues, for example 2:1, 3:1 or greater. Duringperiods of rest, blood flow to core organs can be orders of magnitudegreater than blood flow to peripheral tissue. During periods ofrelatively intense physical activity, cardiac output to peripheraltissues increases and continues for a period afterwards. During periodsof intense physical activity and afterwards, heat produced by peripheraltissues can be greater than heat produced by core organs due to acombination of heat carried in the blood and heat produced by muscles.The thermally conditioned seat system can detect an occupant's thermalcondition (e.g., using a PIR sensor) and adjust the first and secondheat transfer rates accordingly. The first heat transfer rate 76provided by the seat back 14 can differ from the second heat transferrate 78 provided by seat cushion 12 in proportion to a difference in anamount of heat produced or absorbed by the occupant in correspondingregions conditioned by the seat back 14 and the seat cushion 12. Forexample, the first heat transfer rate 76 can differ from the second heattransfer rate 78 in proportion to the heat produced or absorbed by theoccupant's body core (region conditioned by the seat back 14), and anamount of heat produced or absorbed by the occupant's buttocks andthighs (region conditioned by the seat cushion 12). This asymmetricthermal management approach provides enhanced comfort to the occupantcompared to the symmetrical thermal management approach shown in FIG.3A.

In one example mode of operation, the first thermal conditioningassembly 28, for example, the first cooling device 28 a, is initiatedprior to the second thermal conditioning assembly 30, for example thesecond cooling device 30 a. The first and second heat transfer rates 76,78 are different for a first period of time, and the first and secondheat transfer rates 76, 78 subsequently become substantially the samefor a second period of time. Thus, asymmetrical heat transfer rates areprovided initially. Over time, the heat transfer rates provided by theseat back 14 and seat bottom 12 may be controlled to provide symmetricalheat transfer rates. This may be accomplished, for example, bydecreasing the power to the seat back to correspond to the powerprovided by the seat bottom, or vice versa. In one embodiment, afteremploying asymmetric cooling, a control loop may be entered in which theasymmetric cooling is continued or is migrated toward symmetric coolingor some combination based on any known inputs or sensors.

The vehicle manufacturer only affords a seat manufacturer a limitedamount of power consumption for climate controlled seats. The disclosedthermal conditioning system 68 makes better use of the available powerfor the climate controlled seat. The first thermal conditioning assembly28, for example, the first cooling device 28 a, draws a first currentwhen cooling initially, and the second thermal conditioning assembly 30,for example, the second cooling device 30 a, draws a second currentinitially. The first current is greater than the second current by atleast a 2 times, for example. In one embodiment, the first current isgreater than the second current by at least a 4 times, and in anotherembodiment, the first current is greater than the second current by atleast an 8 times. Cooling the occupant's back quickly has a greaterimpact on overall occupant thermal comfort than cooling the occupant byevenly distributing the available current between the seat back and seatbottom. Voltage and/or current monitoring of the vehicle battery and/orthe thermal management components can be used to regulate the disclosedclimate seat. The asymmetric thermal management system can be operated,regulated, or optimized according to voltage input. Output voltage todevices can be directed to maximize thermal comfort.

The heating elements 42 in the seat back 14 and seat cushion 12, whichrespectively provide third and fourth heat transfer rates 80, 82 (q₃,q₄) may be controlled in a manner similar to the cooling functiondescribed above, if desired.

It should also be understood that although a particular componentarrangement is disclosed in the illustrated embodiment, otherarrangements will benefit herefrom. Although particular step sequencesare shown, described, and claimed, it should be understood that stepsmay be performed in any order, separated or combined unless otherwiseindicated and will still benefit from the present invention.

Although the different examples have specific components shown in theillustrations, embodiments of this invention are not limited to thoseparticular combinations. It is possible to use some of the components orfeatures from one of the examples in combination with features orcomponents from another one of the examples.

Although an example embodiment has been disclosed, a worker of ordinaryskill in this art would recognize that certain modifications would comewithin the scope of the claims. For that reason, the following claimsshould be studied to determine their true scope and content.

What is claimed is:
 1. A thermally conditioned seat comprising: a seatportion constructed from a first material includes a seat supportstructure having a central support region and adjacent side bolsterslaterally spaced apart from one another a width, and a recess isprovided in the central support region and includes an aperture; aporous material is arranged in the recess against the first material; asecond material arranged against the first material and the porousmaterial; a cover includes an air permeable layer and an aesthetic layerthat provides an exterior seating surface, the air permeable layer isarranged against the second material, and the aesthetic layer hasperforations; a blower is associated with the seat portion and is influid communication with the aperture, the blower configured to supply afluid through the aperture to the porous material through the recess,the fluid configured to pass from the porous material to the airpermeable layer and out the perforations.
 2. The seat according to claim1, wherein the first material is polyurethane foam.
 3. The seataccording to claim 2, wherein the seat portion is one of a seat bottomor a seat back.
 4. The seat according to claim 1, wherein the width is afirst lateral width, and the porous material has a second lateral widththat is less than 75% of the first lateral width.
 5. The seat accordingto claim 4, wherein the second lateral width is 35-65% of the firstlateral width.
 6. The seat according to claim 2, wherein the porousmaterial is a breathable spacer material.
 7. The seat according to claim6, wherein the second material is fleece.
 8. The seat according to claim7, comprising heating elements supported on the fleece on a sideopposite the porous material.
 9. The seat according to claim 6, whereinthe air permeable layer and the aesthetic layer are joined to oneanother at stitched seams.
 10. The seat according to claim 1, comprisinga thermoelectric device arranged between the blower and the recess, thethermoelectric device configured to cool the fluid.
 11. The seataccording to claim 1, wherein the second material is impermeable and hasan opening, the fluid is configured to pass from the porous materialthrough the opening to the air permeable layer and out the perforations.